1. Field of the Invention
The present invention relates to control modules for seat belt retractor and seat belt retractors, and more particularly to an electric-driven control module for seat belt retractor that winds a seat belt using a motor and such a seat belt retractor.
2. Background Art
Conventionally, as a seat belt retractor, an electric-driven seat belt retractor is known that winds a seat belt using a motor (see JP Published Patent Application No. 2001-187561 A, JP Published Patent Application No. 2006-89037 A, JP Published Patent Application No. 2002-321597 A, and JP Published Patent Application No. 2001-130377 A, for example).
In general, judging that there is a high possibility of a vehicle colliding with an obstacle, an instruction is input to a control circuit of a seat belt retractor so as to wind a seat belt. In accordance with this winding instruction, the control circuit feeds a driving current so that a predetermined winding torque is generated at the motor, thus making the seat belt wound around a spool. This lets a passenger of the vehicle closer to a seat so that there is substantially no space therebetween, thus enabling to reduce shock to the passenger when the vehicle collides with the obstacle.